Saurians front the Lffwet- Greensand. 63 



terminating one end of a transverse section of a compressed and bent 

 thick plate of bone. 



Metatarsals. — These bones, Mr. Owen says, exhibit the charac- 

 teristic irregularity of length of the crocodilian metatarsals. Of two 

 imbedded in the rock, and considered by the author to be the inner- 

 most and second, the former or smaller measured one foot in length, 

 and the latter two feet, having a diameter of eight inches at its 

 greater and of four inches five lines at its narrowest or middle part, 

 and of six inches at its other extremity, which M'as imperfect. The 

 whole of the bone within the compact outer crust consisted of cells 

 varying from a half to two-thirds of a line in diameter. Portions of 

 four other detached metatarsals are described. 



Ilia, Ischia, Pubis, and Coracoid Bone. — These bones, the author 

 states, also conform to the crocodilian type. The remains of the 

 ilia are flat and nearly straight, and they gradually but slightly 

 widen towards one end. Of one ilium, a portion, twenty-five inches 

 long and ten inches across at the broadest end, is preserved, and of 

 the other a fragment twenty inches in length. 



The mesial extremities of the pubis and ischium are preserved in 

 the same block of stone. The pubis, Mr. Owen states, differs from 

 the crocodilian type in its greater breadth. The portion exposed 

 in this block is principally convex, but it becomes concave towards 

 the opposite or median margin. At its broadest part it is thirteen 

 inches across, and its length is seventeen inches. This expanded 

 extremity is rounded, and the diameter of the corresponding ex- 

 panded extremitj'^ of the ischium, M'hich is obliquely truncated, is 

 nine inches. In another block of stone the expanded extremity of 

 the opposite pubis is preserved, and measures fourteen inches across 

 and twenty-two inches in length. 



The bone, considered by Mr. Owen to be a coracoid, is two feet 

 in length and seventeen inches in its greatest breadth, and it varies 

 in thickness from three to five inches. The breadth of this bone in- 

 dicates, the author states, the great development of the muscles de- 

 stined for the movement of the fore -leg, whence he infers that the 

 anterior extremities were more powerfully and habitually used in 

 progressive motion than in the Crocodiles, and that they were con- 

 sequently provided wdth a webbed modification of the hand. 



Mr. Owen then enters upon the question of the identity or affini- 

 ties of the Hythe remains with any of the known marine genera of 

 the saurian order, the texture of the long bones being conclusive 

 against their having belonged to the terrestrial genera, the Iguano- 

 don and Megalosaurus. 



The length, thickness, and indications of condyles in the femur, 

 and the length, thickness, and angular form of the metatarsal bones, 

 place, he says, the Plesiosaurus and the Ichthyosaurus out of the 

 pale of comparison ; as well as the Mosasaurus, the locomotive ex- 

 tremities of which are considered to have been flattened paddles. 



The superior expanse of the pubis and the broad coracoid (.''), with 

 the form of the femur and tlie gigantic proportions of the bones, for- 

 bid a reference to any subgenera, recent or extinct, of the crocodilian 



